package com.wy;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IProjectNatureDescriptor;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.ResourcesPlugin;

import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.contentassist.CompletionProposal;
import org.eclipse.jface.text.contentassist.ICompletionProposal;
import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.jface.text.contentassist.IContextInformationValidator;

public class ProjectContentAssistProcessor implements IContentAssistProcessor {

	@Override
	public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int offset) {
		// TODO this is logic for .project file to complete on nature and project
		// references. Replace with your language logic!
		String text = viewer.getDocument().get();
		String natureTag = "<nature>";
		String projectReferenceTag = "<project>";
		IWorkspace workspace = ResourcesPlugin.getWorkspace();
		if (text.length() >= natureTag.length()
				&& text.substring(offset - natureTag.length(), offset).equals(natureTag)) {
			IProjectNatureDescriptor[] natureDescriptors = workspace.getNatureDescriptors();
			ICompletionProposal[] proposals = new ICompletionProposal[natureDescriptors.length];
			for (int i = 0; i < natureDescriptors.length; i++) {
				IProjectNatureDescriptor descriptor = natureDescriptors[i];
				proposals[i] =
						new CompletionProposal(descriptor.getNatureId(), offset, 0, descriptor.getNatureId().length());
			}
			return proposals;
		}
		if (text.length() >= projectReferenceTag.length()
				&& text.substring(offset - projectReferenceTag.length(), offset).equals(projectReferenceTag)) {
			IProject[] projects = workspace.getRoot().getProjects();
			ICompletionProposal[] proposals = new ICompletionProposal[projects.length];
			for (int i = 0; i < projects.length; i++) {
				proposals[i] = new CompletionProposal(projects[i].getName(), offset, 0, projects[i].getName().length());
			}
			return proposals;
		}
		return new ICompletionProposal[0];
	}

	@Override
	public IContextInformation[] computeContextInformation(ITextViewer viewer, int offset) {
		return null;
	}

	@Override
	public char[] getCompletionProposalAutoActivationCharacters() {
		return new char[] { '"' }; // NON-NLS-1
	}

	@Override
	public char[] getContextInformationAutoActivationCharacters() {
		return null;
	}

	@Override
	public String getErrorMessage() {
		return null;
	}

	@Override
	public IContextInformationValidator getContextInformationValidator() {
		return null;
	}
}